bands across a crystal grain, observed on a polished and fetched section, the crystallographic orientations of which have a mirror image relationship to orientation of the matrix grain across a comparision plane which usually is paralleel to the side of the band (see: twin), ribad piki tera poleeritud ja söövitatud lihvil, mille kristallograafilised orientatsioonid on peegelpildis võrreldava maatriksi tera tasandiga, reeglina paraleelne ribade servaga (vt kaksikkristall)